I still wish they'd throw in a toggle to turn off/hide white guns. Also O2 tanks having a blue glow is bullshit. It's like when mission items were green in BL1, too easy to confuse it with a gun. At least make 'em white, no one looks at white guns.
I'm pretty sure BL2 had the same deal though, I think classes of guns/elements "unlock" by level. Fire first, then other elements, and it takes a while for rocket launchers to show up (not that they don't suck because boyyyy are rocket launchers pointless)
Yeah I think there is some sort of internal switch that in the late teens is when loot gets good. I haven't even seen laser weapon yet.